code: def test_constraint_from_config(self):
      constraint_fn = constraints.Constraint()
      config = constraint_fn.get_config()
      recreated_constraint_fn = constraints.Constraint.from_config(
          config
      )
      self.assertIsInstance(
          recreated_constraint_fn, constraints.Constraint
      )
  
file_path: keras/keras/constraints/constraints_test.py
imports: import numpy
  from keras import backend
  from keras import constraints
  from keras import testing
label_desc: Use image node_id 8 for calling the ConstraintsTest obj's underlying member method code with example usage: obj.test_constraint_from_config() without return types